• Sun's TreeTable
• an enhanced JTable with support for sorting, searching, and sizing.
• Jeppers: a complete spreadsheet component.
• Editable Swing controls A set of Swing controls (Tree and Table) able to add/edit/remove their elements.
• Generic Table Model Table Model built around simple list of objects; an example from jga: Generic Algorithms for Java

Trees

• FlexiTree a tree component for very large (300,000+) sets of nodes.

Enhanced File Choosers

• 'typed key seek' support http://www.oxelis.com/oss/JFileChooserX.html
• Better looking among others http://uic.sf.net/index.phtml?target=product/FileChooser/view.phtml

Font Choosers

• http://www.cruftworks.com/software/JFontChooser/
• http://www.zbluesoftware.com/javacomponents/
• http://fontwidget.sourceforge.net/
• http://uic.sourceforge.net/index.phtml?target=product/FontSelection/view.phtml

Color Pickers

• http://uic.sourceforge.net/index.phtml?target=product/ColorSelection/view.phtml

Editing Components

• Java HTML editor

Date Pickers

• http://www.java-calendar.com
• http://www.javadatepicker.com/index.html
• http://sourceforge.net/projects/mseries/
• http://sourceforge.net/projects/dateselector/
• http://sourceforge.net/projects/javadatepicker/
• http://toedter.com/en/jcalendar/index.html
• http://uic.sourceforge.net/index.phtml?target=product/DatePicker/view.phtml

MDI

• a scrollable MDI JDesktopPane http://jscroll.sourceforge.net/

Wizards

• http://wizard.dev.java.net/
• http://jwizardcmponent.sourceforge.net/
• http://sourceforge.net/projects/gandalf/
• http://sourceforge.net/projects/jwf/
• http://jlwizard.sourceforge.net/
• http://uic.sourceforge.net/index.phtml?target=product/Wizard/view.phtml

Other

• Led Ticker - text rotation component http://www.ledticker.net
• Directorychooser, Fontchooser, Taskpane, Property editors, ... http://common.l2fprod.com/
• a collection of advanced components (need to look at it more) http://ajax.sourceforge.net/salsa/
• JCommon http://www.jfree.org/jcommon/index.html Lots of cool stuff including a date picker, font selection, about frames, sortable tables, and wizards
• Database Hooks http://swingset.sourceforge.net/
• Barcode generator http://barbecue.sourceforge.net/
• JBarcode Bean http://jbarcodebean.sourceforge.net/
• Boolean Expression Editor http://beej.sourceforge.net/
• Property editor. a table list with autogenerated editors for whatever object you put in it.
• JModalWindow supports modal functionality, similar to JDialog, without blocking all frames.
• SwingSet open source Java toolkit that allows the standard Java Swing components to be made database-aware.
• JCustomizer generic and persistent customization of every Java Swing/AWT GUI at runtime: fonts, colors, texts, accelerators, ... A nice accompaniment is a WYSIWYG access to internationalization without programming efforts.
• JPrintPreview print preview dialog for any Java application
• PSwing Components combo box, date picker, color picker, font picker, and integer text field.
• Float API provides multiple floating-Window JPanels which can be docked in other JPanels.
• Animated Label - version of JLabel suitable for simple animations

Java Desktop's swing component list http://www.javadesktop.org/rollups/components/index.html